The present invention relates to double wall units forming separate inner and outer compartments for storage of inflammable liquids, such as gasoline, above ground. Heretofore, there have been many different structures proposed for storage of inflammable liquids below ground, and a variety of structures have been proposed for transport and/or storage of inflammable liquids above ground. In storing inflammable liquids above ground, it is essential that controls be provided re any possible leakage of the liquid from one or both of the tanks; the vapors from the stored inflammable liquid, such as gasoline, must be vented from the tanks or be otherwise handled in a safe manner; the structure must be as fireproof as possible and be resistant to impacts; and gradual deterioration of the structure must be observable. Also, the structure should be difficult to damage by vandalism, and the structure should be earthquake proof, if possible.
Efforts have been made in the past to provide a unitary gasoline storage and vending apparatus that can be moved from place to place, as desired, for vending of gasoline. The possibility of automatic vending of gasoline from a storage tank unit at a remote area, or during the night when other gas stations or suppliers would be closed, provide interesting commercial possibilities for use of self-contained gasoline storage and vending units. These units particularly lend themselves to above ground storage of gasoline.
A number of different patented constructions have been proposed for storage of liquids, and they include U.S. Pat. Nos. 1,453,983 and 2,558,694. It still is very desirable to provide an improved above ground storage facility for gasoline, which facility is safe in construction and use, is durable, and would provide a mobile gasoline storage and vending unit.